1. Field of the Invention
The present invention relates to agricultural irrigation systems. More particularly, the invention relates to a method and system for orienting a solar-powered irrigation system to permit optimal charging of the systems' batteries.
2. Background
Agricultural irrigation systems such as central pivot irrigation machines are commonly used to irrigate crops. A central pivot irrigation machine typically includes, among other things, a central pivot communicating with a pressurized water supply and a series of mobile support towers connected to the central pivot and to one another by truss-type framework sections. A water distribution conduit is supported by the framework sections and a number of sprinkler heads, spray guns, drop nozzles, or other fluid-emitting devices are spaced along the length of the conduit.
The mobile support towers are supported on wheels that are driven by a motor on each tower. Such an arrangement provides satisfactory performance, although it is expensive to provide power to all the motors because long power transmission devices, such as wires, cables, or the like, must extend out to the far reaches of the irrigation system.
Solar powered irrigation machines eliminate the need for power cabling to all the motors and provide other benefits. Such machines typically include a number of solar panels that collect light energy, convert the light energy to electrical energy, and use the electrical energy to power the drive motors on the mobile towers and/or charge batteries for later operation of the motors.
Solar panels produce the most electricity when they face the sun, thus, it is desirable to re-position the solar panels as the sun moves across the sky during the day. One such system for re-positioning the solar panels of an irrigation system is disclosed in U.S. Pat. No. 7,878,429 (the '429 patent), which is hereby incorporated into the present application in its entirety by reference. The '429 patent discloses an irrigation system with a direction control system and a tilt assembly for rotating and tilting its solar panels so the solar panels face the sun as the irrigation system moves across a field while in operation. While this approach is effective, it requires relatively expensive and complex equipment for mounting, rotating, and tilting the solar panels.